Cohabitation
by 8.Years.Of.Silence
Summary: It's a split second choice - probably the only one they have left. But Dean makes it, because it's Cas lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU
1. Chapter 1

_**Summary:** It's a split second choice - probably the only one they have left. But Dean makes it, because it's his brother lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU_

 _ **A/N**_ _: Apparently I didn't have enough to do with The Road So Far (This Time Around). Nope, obviously I needed another story. Damn you, plot-bunnies! Oh well, this one is significantly shorter. Hope you guys enjoy!_

 _ **Story Warnings** : Rated T for some swearing, violence, and dark themes. Takes place somewhere after 12.12 Stuck in the Middle With You._

 _ **Chapter Warnings** : Angst, bombs, brotherly love, partial character death I suppose? _

-o-o-o-o-o-o-o-

 **Cohabitation**

Chapter 1

-o-o-o-o-o-o-o-o-

 _ **Cohabit** ;_ _v. To exist together._

They stood on either side of the barn doors, weapons gripped in sweaty palms, breaths steady, shoulders taught. Across the length of the door, Sam glanced at his brother, whose game face was securely in place. He was pissed, and rightly so. Sam, on the other hand, was more worried than angry, as was the tendency between the brothers.

Dean caught his eye, and he gave a single, solemn nod.

His brother rounded on the wooden door, slamming it open with a well-aimed kick. Sam followed immediately behind, gun raised over Dean's shoulder to cover him as the two cleared the corners. When no attacker presented themselves, Sam finished a visual sweep of the barn, gun raised to every dark corner, the stalls in the back, long abandoned, and the loft above.

"Cas!" Dean ran forward to the center of the barn where their friend was tied to one of the posts supporting the loft. The angel, beaten and bloody, was propped against the wooden structure, legs spread out in front of him, bound to the post by thick, silver chains stretched across his torso. Dean slid to one knee beside their friend, hands automatically reaching out to wrap around the side of his neck and tap the man gently on the cheek. "Buddy? Cas, come on, can you hear me? It's us!"

"Room's clear," Sam muttered as he tucked his gun into his waistline and dropped beside the two. Dean was still trying to rouse the angel, whose head lolled to the side but was beginning to show signs of consciousness. Sam made to check the rest of their friend over for injuries but drew up short. He threw his hand out, grabbing his brother's arm and halting his movement. "Dean….don't move."

"What? What are you talking-" Dean shot an incredulous glance to his brother, but Sammy wasn't looking at him. He followed the terrifyingly blank expression on Sam's face, focused solely on Castiel's chest. The older Winchester froze immediately as he spotted what he had previously overlooked in favor of making sure their friend wasn't dead. "Whoa."

Welded into the chains by what looked like liquid metal long hardened, was a bomb. It wasn't your Saturday morning cartoon sticks of dynamite or procedural cop show flak vest complete with C4. This looked more like something out of a bad sci-fi show, with four glass cylinders filled with glowing, ethereal blue liquid, connected to a digital readout flashing numbers in clear, deadly white LED.

 _06:14…06:13…06:12…_

"Okay….Okay." Dean stepped back from Castiel slowly, releasing the angel's neck and tearing off his jacket. "We gotta get him out of there. Any ideas?"

Sam very carefully leaned in to examine the device. He didn't dare touch any of the connecting tubes or wires, some of which were definitely not of human design or technology. There was no removing the bomb from the chains. It looked to be permanently welded in place, added after Castiel had been bound by the heavy chains. Sam grimaced at the thought, realizing that the material of chain was melted in some places, warped into the mechanism. It honestly looked like someone had poured liquid silver on top of the angel and stuck a bomb in the middle of the mess.

He prayed Cas hadn't been conscious through it.

 _05:46…05:45…05:44…_

Slowly and with every precaution he could, he reached between two rings of chain and pulled at Castiel's trench coat. The younger Winchester sucked in a breath when his worst fears were confirmed by the lack of give. The smelted metal had been applied atop the angel, seeping into his clothes and skin and solidifying into place, sealing the two together.

They weren't getting Castiel away from that bomb. Not in one piece.

"Dean-"

"Can you make it stop?" Dean interrupted him, knowing full well what he was about to say. He could see it in Sam's eyes: those pained, puppy dog, soul-brown eyes that looked his way in absolute terror. Even if he hadn't seen the evidence for himself, Dean knew what Sam was thinking. "Turn it off, or something?"

"I don't even know what _it_ is," Sam countered, rocking back on his heels to stare at the device. He'd never seen anything like it, and he had just as good a chance of blowing the three of them up five minutes sooner than he did at stopping it.

"D'n, S'm."

"Hey, hey, buddy, you with us?" Dean leaned back in, cupping Cas's neck once more as the angel opened weary, pain-ridden blue eyes. "That's it. Morning sunshine."

"It isn' mr'ng." Cas stared up at them with squinted eyes, blinking through the blood dripping over one eye and the other already swelling up from what would be a hell of a black eye. He tried to sit up, only to grunt and gasp at the abrupt reminder of his injuries and the lack of mobility presented in the crushing, pinching chains wrapped around him. "Wh't h'ppn'd? Wh'r are we?"

"You got nabbed by those douche-nozzles," Dean bit back, jaw clenched and words bitter with anger and the need for revenge. "But we're here now, and we're gonna get you out."

"Out?" Castiel's head lolled to the side before his chin found respite against his chest and he stared down at the ticking numbers reading out across his torso. It took him a moment to parse their meaning, to remember the beating he had taken at the hands of the British Men of Letters. Being thrown against the post and bound in the abandoned barn, the hot smelt of liquid metal pouring over his vessel and the excruciating pain that followed.

His eyes widened as he stared down at the bomb, ticking away on his torso.

 _05:01…04:59…04:58…_

"You ha'f to get out," he mumbled against his chest, lifting his head to look at the two brothers – _his brothers_ – with terror-filled eyes. He repeated himself, louder and with more effort and urgency, "You need to leave. Now!"

"We're not leaving you, Cas," Sam answered immediately, still staring at the mechanism. He was fairly certain which of the wires was the lead, and had identified one false lead so far, or what he was pretty sure was a false lead. But real bombs weren't like the movies. It wasn't a simple 'cut this wire and the clock stops' and, to be honest, Sam wasn't an expert. Bomb disarmament wasn't exactly in their daily routine.

"Call Garth," he instructed his brother, standing up to pull his own jacket off, already sweating in the Louisiana night-time heat.

"Garth?" Dean sounded less than confident in his brother's choice of bomb expert, but he already had the phone pressed to his ear, ringing.

"He, uh, told me he used to keep a flak jacket in his armory." Sam huffed out a small laugh as he knelt back down carefully beside the angel. "He may know how to disarm one."

"Yeah, don't think this is your standard flak setup, Sammy," Dean mumbled even as he started pacing. "Pick up, pick up. Come on! No answer."

"Try again," Sam demanded, even though his brother was already doing just that.

 _04:17….04:16….04:15…_

"Sam, l'sten to me." Cas's pleading blue gaze locked on his and Sam raised his eyes from the device to his best friend. "It's n-not explosive. I's grace."

Beside them, Dean froze in his frantic movements, dropping the phone to his side. "What?"

"Cas, what do you mean, it's grace?"

The angel glanced down at the bomb strapped to his chest before looking between the brothers. "An angel's grace. They said they had it…for a while. M-mixed with holy oil and a ch-chemical I didn't…."

Sam glanced down at the ethereal blue liquid flowing between the containers. The chemical was probably nitroglycerin, given the viscosity of the material and the lack of additional coloring. Putting the three together with an incendiary…. The near college-graduate and brains of the team rocked back as he realized what Cas was trying to say. He looked up at Dean, who stared at him with a clear 'what?' expression.

"The blast could take out a city block," Sam whispered, almost numb. "Dean, this thing is going to clear a…a three hundred foot radius, at a minimum."

"What are you saying, Sammy?"

"You have to get clear." Cas stared up at Dean, the desperate plea in his eyes was almost the hunter's undoing. "You need to run."

"We're not leaving you." The hunter moved behind the angel, away from those pained blue eyes and started tugging on the chains behind him. He couldn't even find where they ended. There was no lock, no tether. The chains appeared endless, which made no friggin' sense.

"Dean, if we don't leave now, we won't get clear of the blast," Sam said quietly, though he didn't make any move towards standing up either.

"Then figure out a way to stop it, Sam! We're not leaving." Dean gave the chains an experimental tug, but they barely budged and Cas only groaned in response. He stood back, telling Cas not to move, and trained his gun on one of the chains. The ricochet was loud, but thankfully non-damaging. Some of the post chipped away, raining bits of splinter down on them. Unfortunately, the heavy link had little more than a chink in the metal to show for the effort and noise.

"Will you just listen to me?" Cas struggled to turn his head, to look at the hunter behind him and then the one in front, carefully pulling apart the various wires and tubing. "You need to leave. _I_ need you both to leave. Please!"

Sam didn't bother answering, focusing solely on identifying which wires he would need to cut, splice together, and disconnect. Dean, however, rounded back on the angel, kneeling in front of him with a firm hand gripping his shoulder tight.

"You listen to me, you son of a bitch. You're family. You don't leave that behind."

Cas grit his teeth and let out a groan. His gaze grew more livid than desperate. "So three will die instead of one?"

Anger, Dean could deal with. He was good at anger. "If that's what it takes."

The angel let out something between a keen and a snarl, staring at the two humans who had made him what he was, who meant more than the world to him, who were going to remain the stubborn idiots he'd first fallen for, and would now die beside.

 _03:36…03:35….03:34…_

"Okay, Dean, I think I got it." Sam leaned back on his calves, pulling his pocket knife out and flipping it open. He gave his brother a harried look. But Dean only nodded solemnly back, complete faith in his younger sibling. "Here goes."

The three Winchesters collectively held their breaths as Sam cautiously slipped his knife under the first wire. Nitroglycerin was infamous for its instability, particularly to physical shock. The fact it hadn't set off with Dean's haphazard shooting was a miracle. Sam didn't even want to test what a minor bump to the device might do when mixed with a volatile substance like grace.

To be honest, they were lucky the grace hadn't ignited the chemical on its own already.

He put as much pressure as he dared against the blade, gritting his teeth when it refused to cut through the wire. With a frown and confusion filtering across his brow, Sam repositioned the knife and tried again. Nothing. The plastic protection around the wire didn't even dent.

 _03:03….03:02….03:01…_

Sam sent his brother a worried look, then tossed caution to the wind and started a steady rhythm of sawing motions with the blade. Still, nothing.

"Try mine." Dean held out his bowie, which was impractical for a delicate operation like this one, but Sam didn't really care at that moment. He swiped the knife from his brother and pulled at the wire with more strength then ever should have been needed.

The length of wire strained against the edge of the blade, but held firm.

"Oh, what the hell!" Sam fell back with a shaky breath, staring at the undamaged device, steadily ticking towards their death. He grabbed at the plastic shealth, rubbing it between his fingers. Runes lit for just a moment, reading out along the wires that fed back into the device before they faded. A protection spell. He looked back at his brother, seeing the same wide-eyed, 'we're screwed' expression written over his face.

Dean swallowed, looking back down at Castiel. They didn't know what else to try. With a furious growl, he launched himself back to his feet and threw his phone back up to his ear, once more dialing Garth, not that him answering would do them much good now.

Sam met Castiel's gaze, and didn't know what to say. "Cas…"

"You can still get out, Sam," the angel breathed, imploring the two men to leave. "Please. You can still make it."

The young hunter seriously doubted that, given the several hundred feet they would need to run in less than three minutes now. And his estimate was likely a gross under-calculation, given the ingredients and amount of them sitting on Cas's chest. Not that they'd ever leave the angel behind, so it was a moot point either way.

"Still no friggin' answer!" Dean chucked his phone across the barn, watching it shatter against the old wooden walls. He dropped beside his brother and his best friend, panting in anger and fear. "Cas…"

"It's okay, Dean."

"No, it's not! I'm gonna kill those bastards."

Cas gave him an almost pitying look that Dean could read as more, as sorrow and acceptance and love, only through years of knowing the angel. He didn't want to see it though, didn't want to acknowledge what their failure meant in those blue eyes.

 _02:12….02:11….02:10…_

Sam went back to pulling at the wires, sawing at them with the blades, but whatever magic had built the device and bound it to Castiel's chest also protected it from tampering. He even got to the point of jostling the thing enough to know the spell work was keeping the nitroglycerin stable from exterior stressors as well. This bomb wasn't going off until it was meant to – which was likely an exact calculation on those measured bastard's behalf, knowing when Sam and Dean would show to save their friend.

Dean cupped the angel's neck again, holding onto him with both hands as he stared into his best friend's eyes. "We're not leaving you, Cas."

The angel let out a broken sob, a couple tears slipping free of his lashes as he looked up and away before meeting Dean's steadfast gaze. He nodded, though it looked like it cost him the world to do so.

Sam glanced at the two, catching his brother's gaze. He saw the end there. But, despite walking into this with every hope that they would find Cas alive and bring him home…there were worse ways to go. He gave a small nod to his brother, whose return gesture said the same without words.

 _01:46…01:45…01:44…_

"Cas." The silence that had filled the barn for what was only seconds, but felt like minutes, was broken by Dean's voice. Blue eyes looked up once more to lock on the hunter, who was staring at him with a mix of emotions he did not immediately understand. "Is this thing tied to your grace?"

"What?" He squinted at the human before him, not understanding the question or the purpose behind it.

"Your grace, is it intact or is it attached to the bomb somehow?"

Sam lifted his head at the thread of desperation in his brother's voice, the vestiges of a crazy plan that had sparked hope in those green eyes. The younger of the two didn't know what it was Dean was getting at, but he'd take any Hail Mary his brother was able to pull out of thin air right about now.

 _01:31…01:30…01:29…_

"No," Cas mumbled, eyes darting back and forth as he sought within himself for the state of his battered grace. "It's intact."

"Okay. Okay." Dean nodded absently, almost to himself. He cupped either side of Cas's face, bringing those eyes back up to meet his. "Then I'm giving you my permission."

Cas frowned, eyes squinting tight in confusion and pain as he was unable to parse what Dean was talking about.

"Cas, I'm saying yes."

Sam stiffened beside them, staring at his brother with eyes wide from both shock, worry, and the first inclination of hope. "Dean-"

"Cas, come on, man, it's the only way."

The angel's unearthly blue eyes widened as he finally realized what the human in front of him was suggesting – was _offering_. "No. No, Dean, I won't do that to you-"

"I'm not asking," the hunter barked back, thumbs tapping the sides of Castiel's face. "We're running out of time! You climb your ass on in here until we can find you another vessel."

 _01:19…01:18…01:17…_

But Cas was shaking his head, for all the pain it caused him. "You don't understand. I'm u-used up. I won't…I won't have the strength to leave, not for a while. M-Maybe not ever, Dean."

The hunter clenched his jaw, but the resolution in his eyes never wavered. "You hear me backing out? I'm still saying yes."

"No, Dean…." Cas's voice broke midway as the shattered angel continued to deny him with all the strength he had left.

"Damn it, Cas! Look at me." Dean waited until blue eyes locked on his own, however miserable and pained they were. "You're my brother, man, and I'm not losing you. If that means you riding shotgun for the rest of our lives, so be it. It's better than dying."

He could see the moment he broke through, the moment resolve faltered in the angel's gaze, and he grasped hold of it, tightening his hands against Cas's face. "Come on, Cas. Get your feathery ass over here, already. You got my permission."

Castiel closed his eyes tightly, tears forced past thick lashes to slide down his cheeks. He rested his head against the post behind him and for a moment Dean was sure he was obstinately refusing to save his own life, and possibly theirs too. But then light began to build beneath his skin, filling his throat. The angel keened, voice breaking with a sob before the blinding light took over and he threw his head back against the post, mouth and eyes wide with the white beam.

Sam took a hasty step back as he watched that light engulf his brother, flying through every orifice of his face. It caused his body to go rigid, arms thrown wide and head tilted back as Castiel's grace engulfed him. And then it was over. The barn seemed terrifyingly dark in the absence of that pure light. Dean knelt on the floor, doubled over and braced by locked elbows as he breathed heavily through his nose.

 _00:42…00:41…00:40..._

"Dean?" Sam scrambled back over to his brother, glancing at the ticking bomb attached to a now lifeless vessel. "Cas?"

His brother groaned, curling his fingers against the straw and dirt of the barn floor. When his eyes shot open, they were pure green. "It's me. It's me, Sammy."

"And Cas?" The younger hunter couldn't help but glance at the limp body slumped against the post in front of them.

"He's in here," Dean confirmed. "I got him."

Sam barely let the words finish forming before he was hauling his surprised brother to his feet and all but dragging him as fast as he could out of the barn. Dean, unprepared for the sudden movement, stumbled along beside him as Sammy ran as fast as he could straight for the Impala, pulling him along behind.

The younger Winchester threw open the passenger door, shoving Dean in and rounding the car as quickly as he could. They weren't going to make it. There was no way they would clear the blast radius, no matter how fast he drove. Still, he threw himself into the driver's seat, catching Dean's hastily – and badly – thrown keys, jamming the square one into the ignition and lighting the engine up as fast as he could in rapid succession.

Dean caught a single glimpse through the still open barn doors of Cas's unconscious body, chained to the post of the loft, time steadily ticking down in neon white numbers. Then Sammy threw the car into gear and gunned it down the dirt drive that had led them to the barn and their friend. He glanced in the rear view mirror at the rapidly shrinking barn behind them, mentally counting down the time they had left. They weren't going fast enough.

"We aren't going to make it," he whispered, fear coloring the last of his words.

Beside him, Dean suddenly stiffened, back straightening and eyes lighting up blue.

Sam glanced at him, then the road, then him again, trying to keep the Impala on course at dangerous speeds. "Cas?"

Dean's head turned stiffly towards him, in a way very alien for his brother. Glowing blue eyes took him in for only a second before a hand shot out, curling over his forehead and coating the world in darkness.

-o-o-o-o-o-o-o-o-

 _ **A/N** : Next chapter should be up in a week. Hope you enjoyed! Please review and let me know your thoughts!_


	2. Chapter 2

_**Summary:** It's a split second choice - probably the only one they have left. But Dean makes it, because it's his brother lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU_

 _ **A/N**_ _: I am SO SORRY for the delay of this chapter. What I thought I had handled in a week exploded in my face. Outside (Real Life) circumstances blew up, my schedule blew up, my plans for this story blew up, the other story blew up. Oy vey! Anyway, all of that aside, I am so sorry that you had to wait like two months for this. I would have absolutely held off posting chapter 1 if I knew what was coming._

 ** _Reviews:_** _Thank you to everyone who reviewed, favorited/followed, or read last chapter. I'll get around to responding to reviews this weekend._

 _ **Question Concerning Slash:** This story will **not** be slash. Though I am a Destiel fan, this tale follows the cannon of recent seasons, with the writers pushing the "Cas is our brother" angle ;) However, I'll be writing as close to canon as possible, so pretty much squint and you'll see it if you want to, just like in the show :D_

 _ **Chapter Warnings** : None! Defensive Dean, Protective/Worried Sam, and a sleeping Cas for all to enjoy._

-o-o-o-o-o-o-o-

 **Cohabitation**

Chapter 2

-o-o-o-o-o-o-o-o-

His vision returned within the span of one blink; less than the time it took for Dean – _Cas_ – to remove his hand from his field of vision, revealing the completely new road they were barreling down at close to eighty. Sam slammed on the breaks, jerking the occupants in the car forward harshly. Seatbelts hadn't exactly been a priority when they climbed in, which seemed pretty darn stupid now, as the Impala went from breakneck speed to all-out nothing in the span of thirty seconds.

Dean made a pained noise as he caught himself on the dash and the windshield, managing not to fly through the thing probably by angelic-aided strength only. Sam slammed into the steering wheel, strong arms keeping him from completely smashing his face into the top of the wheel. Pain jolting up both arms let him know he probably sprained something at a minimum, and he was sure to feel the bruising on his ribs tomorrow.

The Impala idled in the middle of a back-country road, asphalt lit by the moon high in the sky overhead. There weren't any cars in sight and Sam didn't expect to see any on such a little-used road, which was a good thing considering the car had skidded well into the other lane on its abrupt stop.

A thunderous roar broke the air around them. The explosion made Sam flinch and whip around, desperately searching out the back passenger window. Even as the ground trembled from the shockwave, a plume of smoke and flame flickered over the treetops, climbing into the sky about five hundred feet to the southwest of them. Larger pieces of debris, planks of wood and bits of metal, struck the distant edges of the field that bordered the small road, no less than a hundred feet from the Impala. The sporadic meteors ignited small, lazy fires in the marshy long grass, luckily a fair distance away and not spreading much in the soggy terrain. The smell of burning wood and brush was soon heavy in the air around them, even inside the sealed car, and it took no time at all for ash and embers to begin drifting from the sky. Ground zero for that bomb, with that amount of smoke and destruction, had to be a hell of a sight. There was likely nothing left of the barn or the surrounding woodland and fields.

Sam tried not to think about how they had been in the thick of that explosion only seconds ago. Their latest close call. If the finite trembling of his hands all the way through to his chest was any indication, he wasn't doing a great job of it. The sound of the Impala's passenger door swinging open ripped his attention away from that plume of devastation.

Dean had one hand on the door, half a foot struggling to find its way out of the car to find purchase on the ground. He didn't make it, abruptly giving up the struggle to climb out of the car in favor of doubling over the seat and throwing up on the road below.

"Dean!" Sam shoved his door open, climbing out in a hurry. He moved around the front of the Impala, coming to the side to help support his brother who looked about half a second from falling out of the car and into his own mess.

Which was… oh shit, mostly blood. And he was still throwing it up.

"Dean! Dean, man, hang in there." He propped his brother back up, trying to keep him on the Impala's seat but still hanging over the edge so that any mess made it to the road and not the car. Dean would kill him once he could breathe again if he let the Impala get a hamburger helper makeover.

His brother's head lolled to the side and pale, glowing blue eyes opened slivers to stare at Sam. The hunter immediately took a step back, surprise coloring his body before his mind caught up to override the instinctual flinch. He reached forward, grabbing onto the angel's shoulders. "Cas? Castiel!"

The light faded from those eyes, leaving them terrifyingly empty for a moment before they closed.

"Cas!" Sam was hesitant to shake him in case of internal damage, but he did it anyway, albeit gently. Terror stuck thick in his throat. The blood, that fading light – Cas had said he wasn't sure he had the power left back in that barn, yet he'd sent them and the Impala out of the explosion range. Was that why he was throwing up? And what did that mean for his brother, currently serving as his vessel? "Cas?"

Green eyes cracked back open and Sam let out a relieved sigh that at least one of them was still alive. Dean groaned, raising an arm to brush Sam off his shoulder and the younger Winchester let him. He stood a step back from the car, staring down at his two brothers as the flames and smoke of the burning barn flickered in the distance, visible over the roof of the Impala.

"That sucked," Dean mumbled, voice thick with what Sam suspected was blood. "Don't think Cas had the juice to r-really do that."

Sam nodded along, suspicions confirmed but brow still furrowed in worry. "Is he okay?"

"Says he needs rest." Dean's head rolled onto the back of the seat, eyes closing in exhaustion. Apparently, the angel wasn't the only one. The older Winchester looked like he didn't have it in him to keep his head up, and Sam could easily fathom why. Housing an angel was no picnic, and Dean had a drained, hurting one on his hands. "He get the car with that road pizza?"

"No." Sam would have laughed if he wasn't so terrified and grated raw from the roller coaster of emotion the last hour had been. "No, your car is fine, you jerk."

"Bitch." Dean swallowed and cracked his eyes open once more, managing to look at his brother without moving his head. Despite the fact he sounded liked he was talking through a throat full of pudding, there was real concern and fear in his voice as Dean asked, "You okay?"

Sam nodded, eyes flickering back to the orange and black sky across the field. Dean struggled to turn around and join his brother in watching the plume of smoke through the back window. He didn't have to say anything – Sam could see the same whirlwind of thoughts in his gaze as was going through his own head.

That had been too close. And Cas… Well, it wasn't over yet.

The young hunter walked back around the car, climbed in and put the car into gear once more. She purred in the middle of the road, rearing to get her passengers back to the sanctuary of the bunker. Sam cast a glance at his brother again, but Dean had his head pressed to the window, eyes closed. He was already asleep or soon would be. So Sam put the car into drive and started the long journey back home.

-o-o-o-

All the younger Winchester wanted to do was stop at the first motel he spotted on the road and sleep until he wasn't tired any more, but he forced himself to keep going. The Brits had set that trap specifically for them. While it didn't look like the kind of setup that needed proximity monitoring for success, especially with their advanced equipment and at-will appropriation of satellites, Sam didn't trust the area to be clear. He was not going to be caught unawares for a second time that night, not with his brother in uncertain territory and their angel dangerously vulnerable.

He made it about forty-five minutes down the nearest highway before he could hardly keep his eyes open anymore, resulting in dangerous sways of the car into the other lane and right-hand shoulder. Dean, waking up with the latest corrective jerk of the car, told him to pull in at the next hotel sign. Sam tried to argue – they should get further away – but Dean wouldn't hear it.

"You're practically asleep at the wheel," he muttered without heat or judgement. "We almost died, Sam. Just pull over before you crash my baby."

So he did. They called it quits at a Holiday Inn just off the I-49. By the time they had the keycard in the door and the green light go-ahead, Sam's hands were shaking once more. He didn't even know if it was exhaustion or the delayed adrenaline crash. Dean didn't say much as he pushed into the room and sank onto the first bed without bothering to remove his boots or jacket. Sam pretty much did the same thing, settling on the edge of the second mattress across from his brother.

Dean cracked an eye open. "You sure you're okay?"

"I should be asking you that."

The older hunter closed his eyes with a one-shouldered shrug. "Don't know yet. Cas is alive – we got him out."

"Most of him."

That last moment just outside the barn, seeing Cas's body still chained within, flashed across the inside of Dean's eyelids. The lifeless form of his best friend, sagging against the silver links. That broken down building that was almost their grave, finally going up, taking Cas's vessel – his body – with it. Dean aggressively buried all emotions that sparked up with that singular image. He didn't do emotions and, in this case, he was pretty sure they weren't all his.

The hunter sat up with a groan. He was exhausted and just wanted to sleep till the cows came home, but he knew his brother wasn't going to let them catch the much needed rest before they had this, apparently, urgent conversation. "I don't know what to tell you, man. He's alive."

"And in your head." Sam's expression was soft with relief and exhaustion, even if his voice was tight.

Dean shrugged again, too tired to formulate a real response to that. His body ached like nothing he'd ever felt before, tingling in ways that were anything but pleasant. Like a Magic Fingers on steroids. He figured it was the fallout of Cas using up power he didn't have in order to get them out, like always. But it seemed like tomorrow's problem, one Dean didn't care to think about until then. Right now, he just wanted to join the angel in that oblivion he had slipped into somewhere in the center of Dean's chest, if the weighty feeling dead center in his sternum was any indication.

"We'll figure that part out later."

Sam nodded, realizing there was nothing they could do about it right now anyway, and the two needed to rest before they toppled over. He toed off his boots and made the effort of pulling back the covers of the bed, even as his brother collapsed back with no such priorities. Reaching for the flat pillow, Sam paused, staring at his fingers. They were still shaking.

"He's really okay?" The question was quiet and frankly terrified. It had been too close. And that bomb…. Death may have become something of a dalliance for the Winchesters, Castiel included. But there had been something about that churning vial of grace, rigged to blow, that Sam knew there would be no coming back from.

 _Cosmic consequences_.

He glanced over at his brother, who was staring at him with an identical expression beneath the exhaustion. Dean was hearing the same echoes of Billie's warning. His eyes, locked on his brother, said he understood Sam's fear all too well.

"He's okay, Sammy. Not talking much – think he's wiped out, man. But we got him."

The younger Winchester nodded again, maybe a little too quickly. He curled into the bed, back to his brother and their angel, and sunk into a thankfully dreamless oblivion.

-o-o-o-

They made it back to the bunker late the next afternoon. They'd slept in longer than either hunter had intended. Well, Dean had. Sam was up a sparse five hours after they'd called it, which was still a lot more sleep than he'd expected to get. He wasn't quite like his brother – he liked more than four hours a night. However, what he liked and what his subconscious allowed him were two very different things.

Dean, however, slept another three hours after Sammy started putzing quietly around the room. He slept on through his younger brother showering and dressing, researching angelic possession, grace restoration, and vessels, and going for coffee and breakfast. When Dean didn't rouse at the smell of grease and eggs, Sam started to worry.

But the hunter jumped awake the second Sam's hand landed on his shoulder, eyes shooting open and hand pressing a hunting knife to his brother's chest in one fluid motion. Sam, having experienced that sort of wake-up call from both sides on more than one occasion, stilled until Dean recognized him and collapsed back into the bed with a groan, knife falling harmlessly to the mattress.

He was up a few minutes later, scarfing down breakfast like he hadn't eaten anything in a week and itching for a shower to wipe off the grime of the previous night. For all intents and purposes, he seemed completely normal, but Sam kept an eye on him all the same.

They got on the road an hour later. Cas was still sleeping, his brother confirmed it as soon as Sam asked how the angel was doing, and that was that. They spent most of the day's drive in silence. The younger of the two tried to talk options, but Dean shut him down almost immediately. They needed to wait for Cas to wake up. Sam was well used to dealing with his brother's concern taking the form of irritation, so he didn't push it.

Dean took most of the driving, snubbing Sammy's offer to share the load in favor of bringing up his repeat offenses against Baby's brakes and treads the previous night. Eventually, with a shake of his head and a lot of eye rolling, Sam stopped offering.

They were barely down the stairs into the War Room when Dean announced he was taking a nap. Sam faltered on the final stair, almost eating floor before he caught himself and stared after his brother in equal parts surprise and worry.

"Dude, you just slept like eight hours."

"Yeah, well, I drove the last three," the older Winchester countered obnoxiously. Sam didn't bother arguing that he'd _offered_ to share the drive. Instead, he watched with a furled brow as his brother waved him off and disappeared down the hallway to the dormitory wing.

The hunter stood in the center of the silent bunker, worry gnawing at the newest block of dread forming in his stomach. With a sigh, he dropped his bag on the table, dragging his feet to the nearest chair. He collapsed into it wearily, eyes still glancing towards the door Dean had disappeared through.

Now that they were home, the tension of the last twenty-four hours finally slid off his shoulders, though that tense ball in his gut fought damn hard to hold onto it. But they were safe, and the relief of it was a weight off Sam's chest he hadn't realized had gotten so heavy. The young hunter buried his head in one hand when it finally hit him that he could breathe again. His stomach argued otherwise, but he knew it was a slow-building dread. The kind that came with _'shit's coming but it isn't here just yet'_. His brother was safe, their best friend was alive in a manner of speaking, and they were, however temporarily, out of reach of the British Men of Letters.

 _Cosmic consequences._

Sam closed his eyes and pinched the bridge of his nose. He was depressingly familiar with the signs of early PTSD. Hell, he could tell the difference between trauma and full post-traumatic stress. While he knew this was the former, it posed no less danger or taxation to the mind and body. Dean was probably dealing with something similar, on top of housing an angel.

 _If I decide to do something else stupid, I'll let you know._

Sam pushed out of the chair, rubbing at his arms and the itching need to _do something_. He tried not to let the worry eat at him. Cas was hurting, completely drained, and from what little he could get out of Dean, it sounded like the angel may have sapped up a bit of his new vessel's energy as well to get them out of the explosion range. While Sam was thankful they were alive, he worried about the lasting effects on both his brothers.

So he dug into the research. Despite Dean's request to let it be until Cas recovered some, Sam saw no point in waiting. He immediately ransacked the library, making several looming stacks at the center table and tucking in. They had endless books on angels, research conducted by the Men of Letters and collected data from centuries of observing the supernatural. Sam had been through a healthy majority of it several times before, during the stint with Gadreel, Metatron, closing the Gates of Heaven and Hell, and all the other various divine problems they'd dealt with over the years. He knew that most of that collection had little about angelic possession itself. However, he hadn't been focused on _this_ kind of problem the previous times he'd been through it.

Maybe he had missed something.

Dean might want to wait it out, but Sam knew that was little more than his brother procrastinating what could be an ugly truth. Cas had said he might not be able to leave, and if that ended up the case then the younger Winchester wanted a head start. If the angel wasn't able to eject himself from his brother or find a vessel on his own, they'd need a backup plan. Given how much research there was to sift through and that there was no guarantee what they needed was even there, Sam had a lot of work ahead of him.

His brother and their angel could thank him when they'd inevitably come to realize how difficult living with another person in your head was.

-o-o-o-

Sam stumbled into the kitchen in the early hours of the evening for a coffee refill, only to find Dean in the kitchen cooking up a storm. His older brother greeted him with a grin, flipping burgers in a skillet as he juggled onions and mushrooms in another along with cutting slices of cheese off a cheddar block for melting atop the burgers. All five of them.

"Dean?" Sam couldn't exactly hide his concern. Worried curiosity, really. "Are we expecting company?"

Maybe mom had texted him and was on her way by.

"Huh?" Dean glanced down at the five patties and shrugged a little sheepishly. "Woke up starving. I'm famished, Sammy. I figured you'd want one or two, though."

Sam stared at his brother incredulously as he slid into one of the island chairs. The image of his brother scarfing down breakfast that morning came to mind. "You're making _three_ burgers for yourself?"

Dean had the decency of at least looking like a scolded child amidst the defensiveness that flashed across his face. "I'm hungry.

"And…that's not freaking you out?"

The older Winchester rolled his eyes, shooting Sam a warning look. "It's got nothing to do with Cas, alright?" At his brother's raised eyebrows, he amended, "It's got nothing to do with an angel possessing me. Cas just ate through a lot of juice. We need some replenishing is all."

The fact that it was a burger, Cas's famine-worthy craving, was coincidence as well, Sam was sure.

The younger of the two brothers didn't push the matter further, just set his coffee cup down and climbed back off the stool to grab plates and beers. He didn't want to be the bad guy here, he really didn't. He loved Castiel as much as he loved his brother, but at least one of the three of them was being purposefully blind about the situation.

"What are we going to do about him?"

Of course, charging a problem with a battering ram never worked when it came to Dean. All you got in return was your own battering ram back to the head. Approaching problems that his brother didn't want to talk about sometimes took a more subtle, manipulative approach. It wasn't something Sam was a fan of, but as a kid whose childhood goals had been becoming a lawyer, he was damn good at it.

Green eyes avoided his gaze, glaring down at the stove and sizzling burgers as though they were what had gotten them into this mess.

"Dean?"

"I don't know," his brother finally caved, giving the patties an unnecessary flip to avoid looking at Sam. "We're just gonna have to wait until Cas wakes up. See if he can even leave, or if finding him another vessel is pointless."

"We can't just leave him where he is." This was what Sam had been worried about as he watched his brother all day. It was one of the two worst reactions Dean could have, both of which Sam had been fearful of, but fully expecting. His brother wasn't a complicated guy, not when you got to know him. Things boiled down to guilt or anger with him, and all the actions and choices that followed pointed to which base emotion had tripped him up.

If it had been anger, Dean would be brooding and pissy, itching to get Cas a new vessel, frustrated the angel had been captured, and impulsive in the way they went about every next step. It would be a cover for how afraid Dean was, afraid of what had almost happened to their angel, afraid of what still could, and tired of their never-ending crap lives. But it would have manifested itself as anger, irritated and abrasive towards everyone and everything. But most prominently at the angel himself.

They'd been there not that long ago, after all.

 _Cosmic consequences._

In some ways, Sam was glad it hadn't been an Angry Dean he'd woken up that morning. For several years now, Castiel had been struggling with belonging and feeling at home in a family that wasn't blood. Sam knew he and Dean's actions were partially responsible, and he had thought they were doing better. But Angry Dean had a bad habit of undoing all their hard work.

Guilty Dean, on the other hand, had the worst martyr complex Sam had ever seen. Whenever his brother fell into that mode, Sam ended up toeing the edge of his own limits, waiting for Dean to throw himself at the first grenade they found. And sometimes second, third, and fourth. Unfortunately, in this case, that grenade would be Cas, and they were both going to get blown to smithereens in the process.

 _Again_.

"Come on, man," Dean was already countering, pulling Sam from a depressing spiral of thoughts. Sam focused back in on the kitchen, where his brother was giving him the stink eye that said he was approaching his own limits on this conversation. "The guy is hurting. Can we at least wait for him to heal up before we kick him to the curb? _Again_?"

Sam watched his brother's eyes drop away and back to the stove, trying to hide the regret and self-loathing that flashed across his face. Yup, definitely Guilty Dean.

"We're not kicking him to the curb. That's not what this is about."

"Then what is it?" Dean's knuckles were whitening around the spatula in his hand, images of a wrecked angel-turned-newly-human staring at him in dismay as he all but threw him out when the guy had nothing to his name. "Because it sure as hell sounds like you wanting to kick him out."

The younger of the two jammed a finger in his brother's direction, eyes sparking with their own fierce protectiveness. "Do not lob your guilt on me, Dean. That's _not_ what this is. _I'm_ not kicking Cas out."

Dean visibly bit back a response, jaw clacking shut as he looked away, face reddening. The older Winchester wanted to yell, to defend a choice that had never been a choice at all. Only he knew that was bullshit. There had been a choice: Sam or Castiel, and Dean had picked one, loud and clear. He knew that he and Cas had never really cleaned the air about that. _He_ had never truly cleared the air. Maybe that was why he was all for Team-Let-Cas-Stay, when being reasonable and accommodating was usually Sam's gig. Dean cleared his throat, counted to a number a lot higher than ten, and looked back at Sam with more reason in his expression. "Then what is it?"

"I'm talking about you being a vessel right now; the very thing we spent _years_ fighting against. I know how hard you fought being an angel condom. Hell, you changed _destiny_ just to avoid it. And right now, you are way too calm about all of this."

Dean drew his head back, affronted. "Sam, it's _Cas_! Will you stop talking about him like he's one of those dicks! It's _Cas_."

"I get that, and I'm glad that we saved him, Dean. Thrilled, man. Cas is our best friend – he's _family_ , and I can't imagine life without him." Sam had to take a deep breath to hide the cracking in his voice as memories of Cas's body, chained up in that barn, flashed across his mind. He settled fisted hands on the countertop to hide the slight tremor that returned just thinking about the close call. He didn't need Guilty Dean turning mother hen on him when this was about Castiel. "But we can't just ignore that you're basically being possessed, even if it's Castiel doing the possessing!"

The older hunter grit his teeth. He spun around to turn the burners off aggressively and start divvying up burgers onto plates. "It's fine. _For now_ ," he tacked on over his shoulder as Sam immediately threw him a look. "Let's just let him heal up, then we'll worry about the rest, okay?"

Sam was hardly appeased or in agreement. He was still convinced Dean was fighting too much guilt and self-imposed penance when it came to doing right by Cas to see the situation for what it was. But Sam could see it. He'd been a vessel before, twice, and while Castiel was nothing like Lucifer, but angelic possession was still possession. Sam understood the lack of control that came with sharing a body, even the symbiotic living that came with an angel like Gadreel.

He knew his over-protective, controlling brother was not going to handle forced cohabitation well, despite whatever current contentment he had guilted himself into.

-o-o-o-o-o-o-o-o-o

 _ **A/Ns:**_ _Apologies once more for the ridiculous delay on this chapter! I'm not going to stick to a posting schedule for this story, since I'm not confident how my writing calendar looks over the next month. Hooopefully I'll get another chapter up in the next one to two weeks._

 _Thank you for waiting this one out, and I hope you enjoyed!_

 _ **Sam's Behavior** : For those of you thinking Sam's being a bit of a dick towards Cas in this situation, he's just not getting his point across well yet (ah, brotherly communication. It's the best). He's got a good point that Dean's just going to have to learn the hard way._

 ** _Review:_** _Please review. Comments, critique, and encouragement help feed the muse! Unfortunately they can't help my busy schedule, but it's still better if the muse pokes and prods me continuously to make/find/steal time._ ****

 _ **Up Next:**_ _Cas finally wakes up, Dean gets to deal with a roomie in his head he's never had_ _before, and Sam puts his thinking cap on for solutions to their newest dilemma. Damn, but he'd really hoped to never have to use that grace extraction needle again._


	3. Chapter 3

**_Summary:_** _It's a split second choice - probably the only one they have left. But Dean makes it, because it's Cas lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU_

 ** _A/N_** _: So sorry for dropping this story for almost a year. I didn't want to post any new chapters until I had this story fully completely (so I could post once a week with no more of this ridiculous delay) and it seriously took me the last of this year to actually do that. But huzzah! The story is now complete and I will finish posting over the next month :D_

 _Thanks for everyone who favorited/followed and those of you who've come back despite the delay! You are all the best :)_

-o-o-o-o-o-o-o-o-

 **Cohabitation**

Chapter 3

-o-o-o-o-o-o-o-o-

Letting Cas rest until he was recovered enough to give them some state of where they stood took about a week. The first days were the worst. With Dean sleeping on and off about twelve hours total a day and eating three times the food a normal adult male might consume in one meal, tension and worry ran high. Even Dean started getting twitchy and defensive, taking most of his growing concern out on Sam, since he was the most convenient (and only) target.

So when Dean woke up after his more usual four hours on the fourth day and didn't eat the daily contents of an average American four-person household, the two brothers let out a collective breath they'd held since the barn and started breathing easier.

Tensions were still up, particularly anytime Dean caught Sam researching angelic vessels (which was most of his spare time) or when Sam brought the topic up. Dean seemed to be going for gold in the sport of avoidance and denial. Sam wasn't sure if it was all that previous guilt finally built into a wall of pure stupidity and stubbornness, or if something more was going on. But his brother was adamant about baring Cas's grace like a cross on his back.

Sam tried to bring it up several more times, but Dean shut him down each time, insistent that there was nothing they could do until Cas woke up, so would he just drop it.

"I don't get it, Dean," Sam countered during one such discussion after a week of discussions. They stood in the kitchen on perhaps the first day Dean hadn't tried to eat them out of house and home. "You can't just pretend this isn't happening."

"Of course it's happening, Sam. I'm the one with the angel in my head!"

The younger Winchester threw out his arms. "That's exactly my point!"

"What point?" Dean was almost yelling across the kitchen island, sandwich forgotten on the plate in front of him. "All I keep hearing is how you can't leave Cas be. The guy almost died!"

Sam pinched the bridge of his nose. They seemed to only be talking in circles and it was getting old. "This isn't about him. It's about _you_."

Dean pulled his head back, staring at his brother with a furled brow. "What?"

The brunette let out a sigh and pulled out one of the stools to slide his large frame down onto. He locked eyes with his brother, trying to put his sincerity and concern in his expression so that Dean, for once, wouldn't jump on his words with the defensiveness of a mama bear.

"You've got an angel riding shotgun. Right now, it's an unconscious angel, so you haven't had to share the wheel. But when he wakes up, you two are going to have to learn to live together."

Dean fidgeted under his brother's watchful gaze, and ended up rolling his shoulders defensively. "So what. We've all been under the same roof for years now. What's the big deal?"

"What's the-" Sam huffed in disbelief and shook his head. His brother was being purposefully obtuse; Dean wasn't that stupid. "Sharing living space and sharing _head_ space aren't exactly the same, Dean! You're forgetting that I know what that's like."

"You're comparing Cas to _Lucifer?_ "

" _No_ ," Sam replied through clenched teeth. He took a deep breath, reminding himself that when his brother felt cornered he usually attacked by shifting blame. "I'm actually talking about Gadreel. Lucifer isn't the only angel I've served vessel to, you know."

The blonde snapped his mouth shut at that and ducked his gaze, cheeks tinting red. He had been directly responsible for that fiasco, after all, and Sam hadn't pulled punches mentioning it. They had put it behind them over the years, but that didn't lessen the fact it had happened.

"What's your point?" Dean muttered, still not looking at him.

"My point is, you're the biggest control freak I know." His older brother's head snapped up at that, and Sam shrugged. The truth hurt, but right now it wasn't the hunter he was worried about. "You don't like people driving your _car_ , Dean. We're talking about another person driving your _body_. Yeah, you saved Cas's life, but what kind of life is it going to be if he never has the reigns? If he can't talk, can't go where he wants or do what he wants?"

Dean swallowed, finally realizing what his brother had been on about all this time. Sam hadn't been talking about kicking Cas out. He'd been talking about _rescuing_ him. From Dean. Stubbornly, the hunter rallied a defensive, weak as it was. "It's not a prison sentence, Sam."

"Not an intentional one. But if he can't get himself out and we can't find another vessel, you're going to have to learn how to share your body, your _mind_ , with another person." That wasn't even bringing up the fact that his brother was also the most emotionally constipated person he knew. Dean not having a place to hide all of that pain he refused to let anyone see was going to _kill him_.

Dean didn't respond, staring down at his sandwich in distaste. Sam climbed off the stool, pushing it in against the counter.

"Cas deserves more than riding shotgun," he said softly, remembering how hard a time their angel had been having these last few years. He'd struggled with his mortality, humanity, and then his broken grace once more. Sam could still hear Castiel referring to his own resurrection as a punishment like it was yesterday. They'd been getting better these past few months, all three of them. They'd been working on it, but that didn't erase the past or past insecurities.

They couldn't let this become just another fate for the angel. Their friend deserved more. With that soft reminder, he left his brother to his meal, though he had a feeling Dean didn't have much of an appetite anymore.

-o-o-o-

Since that confrontation, Dean put more effort into helping his brother research. Not much, mind you. He'd never been very good at hitting the books, even when he was committed to it and not sulking like a scolded school boy. Still, Sam took what he could get.

It was several days later that Cas finally resurfaced. They were in the library, stacks of books and notes spread between them. Dean had been on the same page long enough for Sam to know he wasn't really reading it. Suddenly he straightened up, pulling his feet off the desk and setting the book off to the side distractedly.

"Cas?"

Sam looked up, eyes wide and brow raised. Dean's eyes flickered back and forth as one often does talking to someone they can't see. Sam set his pen down on top of his notes as he watched his brother anxiously listen to a conversation he could only hear one side of.

"Man, it's good to hear your voice." Dean's face broke into a smile and he sent a relieved nod in Sam's direction. "Welcome back, buddy. You had us worried."

Not privy to the angel's response, Sam gestured at his brother, who only shrugged with a wide eyed expression. It wasn't like he could put it on speaker. He relayed the information Cas was telling him, confirming that he was going to be alright, but he was still weak and would be for some time.

"Are there any reverse effects for Dean?" Sam asked as Dean paused in his dictation. His brother shot him a warning look, but Sam countered it with a bitchface of his own. "If there are any, we need to know now rather than later."

Judging by Dean's pissy expression, he figured Cas agreed with the younger over the older.

"No, he doesn't think so," Dean replied with no small amount of grump in his voice. "Any damage he may have caused would have healed this last week. I told you Sam, I feel fine."

Sam ignored his brother, instead directing his questions at the other occupant of the room. "And you're okay, Cas? I know it was kinda hairy there for a minute."

"Yes, he's fine. No, the situation was hairy, not you- what? That doesn't even make sense, why would Sam be asking that?"

Following the one-sided conversation was like watching a tennis match against a wall, and Sam snorted. Cas must be alright if he was back to misunderstanding colloquialisms and calling them out. The younger Winchester considered telling his brother he could talk to Cas in his own head, he didn't have to speak out loud. But then he'd be sitting in a silent room with no access to the angel. Plus, he spent enough time prying information from his tight-lipped brother as it was. No way he was intentionally closing this avenue before he absolutely had to or Dean figured it out on his own.

"He says he's fine," Dean clarified, the sarcasm in the almost formal comment coming out clear. "There, happy? No, I'm not saying that."

Sam arched a brow.

Dean made a face, ducking his head like a child forced to talk to his schoolyard crush. "He says he's 'touched' by your concern." There was silence for a beat before the older hunter rolled his eyes and added, " _and_ he's glad we're both in one piece."

Sam quirked a half smile at his brother's brooding and embarrassment. "That doesn't sound like Cas."

His brother glared at him. "I paraphrased."

Sam laughed, finally breathing freely after a week of damn depressing tension.

"Cas, now that you're awake, we should talk options." Despite the grin stretched across his face, Sam switched topics back to the less ideal task of figuring out their next step. He didn't know how long Cas would stay awake for, and he had just about reached the end of what he could do without the angel's help and input. He pulled up his notes and the information he'd gathered on vessels and alternatives.

"Sam-" Dean was shooting him another warning look, but whatever he was going to say ended as he furled his brow, listening to the angel in his head. His brow lowered in a deadpan expression of pissed off huffiness, but he relayed the words all the same. "He says that's a good idea."

The brunette sent a smug look across the table and Dean bristled. But Sam quickly launched into the research. The first thing they'd need to establish was whether or not Cas would be able to leave his current vessel, or if he'd need assistance.

"He just woke up, dude. Cool it." The rebuke was followed almost immediately by, "Damn it, Cas, I'm not kicking you out and you're not a burden."

Given he was only audience to half of the conversation, Sam could only guess at Cas's side of it. After all these years, though, he knew the angel well and wasn't surprised in the slightest that Castiel's thoughts were aligned with his own.

Dean was still ranting with his angel, who was apparently grateful for the manner of the save, but disliked that it meant inconveniencing his friend. Sam listened to his brother bounce between flustered and embarrassed, and angry and defensive. It was adorable, in the younger Winchester's opinion (it was about time the two of them had a conversation not derailed by emotional constipation), but it wasn't exactly getting them anywhere, either.

"Let's focus on our options for now, and you two can go back to trading ' _No, after you_ 's when we figure out our next step." Dean shot him another look, but Sam just raised his eyebrows and dared his brother to tell him he was wrong. "Cas, can you leave voluntarily?"

The blonde broke off his heated glare as the angel answered internally. His face fell minutely, but immediately tightened in resolve. So that was a no, and Guilty Dean was picking up the slack faster than it was actual existing.

"Stop apologizing, Cas, it's fine," Dean said flippantly, even as he shook his head in his brother's direction.

"Okay, we figured that would be the case. What about Dean rescinding his permission. If you're not strong enough to leave, would that help, or would it do more harm than good?"

By the way Dean's eyes widened half a minute later and he adamantly and harshly rejected the idea, Sam figured Cas's answer was the shy and hesitant version of 'I should say no but I'm as big a martyr as either of you, and as it's not technically impossible it is therefore a yes in my self-sacrificing brain.'

Dean's firm ' _No'_ was the shorter version.

"You know, you could let Cas have this conversation," Sam mentioned casually as his brother shook off whatever the angel had said or not said.

Dean immediately looked affronted. "It's not like I'm keeping Cas from talking!"

The hunter froze immediately at the thought and panic flashed across his face even as his gaze slid down and out of focus, which Sam was starting to identify as him talking or listening to the angel. "I'm not, am I?"

There was nothing but silence for Sam. Dean eventually flushed a bit in his cheeks and suddenly looked away from his brother: the patented guilty look for the older Winchester.

"Dean?"

His brother chewed on the inside of his cheek, guilt turning into sullenness. So, Dean had been wrong and someone else right. Sam didn't exactly need three guesses to who that could be. "He says he wouldn't do that to me. Wouldn't 'force another's will' on me."

Yeah, not like Sam hadn't seen that one coming, having figured as much back on day one. Dean, on the other hand, was starting to think his brother might have had a point about rescuing Cas from the unintentional prison he and the angel had created in an effort to save his life.

"It's not like that, Cas," Sam rallied with a soft smile, deciding to save the 'told you so' for another time. Dean had enough on his hands, especially since he was only just realizing it. "It wouldn't be by force."

"Hear that?" Dean threw the question into the quiet room, but judging by the lack of shift in his expression, it was silence he got back internally too. He shrugged a minute later when it was still clearly a no-go.

"Alright," Sam shrugged as well. They'd have to do this by patsy. "So unfortunately I could only find one method of removing an angel from a vessel involuntarily."

He was, of course, talking of the grace extraction device he and Cas had previously tested on the residual power residing in him from Gadreel. In truth, Sam had found a second option: rumors of exorcising an angel. Unfortunately, it hadn't panned out. He'd never been able to find the source, only rumors, and he'd wasted days looking for it before finally calling it as information lost over the ages.

It hadn't been easy to let go of it, either. Sam really didn't want the Men of Letter's grace extractor to be their only option. His tone was as hesitant as the rest of him, remembering the agony that experience had been. He didn't want to put either of his brothers through that unless they had no other choice.

Given Dean's confused look was quickly turning stormy, Cas had either filled him in or was pleading the fifth. Sam had a guess as to which one was more likely.

"We can wait until you're stronger, of course," the resident bookworm added with a weak smile. He had no intention of using that thing until he was sure both Cas and Dean were strong enough to take it. "But we should figure out the plan now so we can be ready."

Because there was no telling how long the two could actually survive with one another, especially with Cas stubbornly refusing to assert any control and Dean spiraling into a guilt-laden abyss. Oh yeah, it was going to be a fun couple of weeks while they got this sorted.

"Where are we even gonna find another vessel?" Dean broke in, staring at his brother questioningly. "We gonna trick some other sucker into being possessed?"

Given the way his face darkened and he followed his own statement up with, "Sarcasm, Cas," the angel wasn't a big fan of that option either.

"I've been doing some digging, and I think I may have found a way around it." Sam sorted through the books around him until he found the one he was looking for and handed it to Dean, who raised his brow at the title.

"Golems?"

"Yeah, they're creatures brought to life by magic, usually sculpted from clay-"

"I remember," his brother grumbled, thoughts drifting to the giant of a man who had nearly killed him back in their Nazi fighting days.

"It's the only solution I've found that doesn't sacrifice someone else as a vessel. Golems are empty; they don't have souls." Sam shrugged one shoulder. "Otherwise, we can try to resurrect Cas's body. Maybe Crowley could do something?"

Dean shook his head, and Sam could almost swear he was shaking it for both of them. "Cas says not to involve that douche if we can help it, and I agree."

Which Sam had also figured. It wasn't his first choice either.

"He says he's not sure if he could inhabit a golem for the same reason angels can't possess corpses." Dean leaned back in the chair, translating the information to his own speech pattern as Castiel spoke within him. "Souls act as a buffer between angel and body, so the vessel doesn't burn out. And an angel requires something to grant permission. A golem might not have either problem, cuz they're tough as hell and the spell could work as permission. But he's not sure how to change the spellwork to incorporate his grace as the power source instead of the creator's will."

It was fascinating listening to the mix of his brother and Castiel's voices as one. Not that Cas was speaking; it was definitely his brother dictating. But Dean slipped in and out of Castiel's more formal and informed speech patterns as he relayed the information, half paraphrased and half repeated.

"Great, that's not a no, so I'll take it." Sam passed Dean several sheets of paper, some copied from spell books and others hand written in a speedy scrawl. "I've looked into the spell and possibly altering it. I think it's doable. I'll need your help with it, Cas, but I didn't see any big obstacles there."

Dean read through the papers, lips mouthing the words quietly, though Sam knew Castiel would be able to see through Dean's eyes to read it for himself. His brother wasn't as good at spellwork as Sam was, so he didn't expect Dean to be the one to spot any problems. The blonde was far better at sigils and warding than Sam would ever be, but witchcraft had taken a bit more readily than Sam was actually comfortable admitting. Of course, it had gotten them out of their fair share of issues, so he wouldn't argue with it, either.

After a moment, Dean sat back and nodded, rubbing at his eyes. "Cas says it might work."

Sam broke out in a smile, the first real good news he'd felt since climbing out of the Impala that night, watching smoke billow into the air with both his brothers beside him, alive. "It'll take some more research, but it's a first step."

-o-o-o-

Dean left Sam to his books and his notes. The sasquatch didn't even notice him scoop up his coffee cup and leave the Library, too busy scrawling notes and edits on spellwork for creating a Golem with renewed fervor now that they had a game plan. Dean mentioned getting something together for dinner as he left, but he doubt his brother even heard him.

He entered the solitude of the kitchen with a deep breath, the silence comforting and overwhelming all at the same time. He tossed his cup beside the sink, the clatter breaking up the empty room.

Now that he was alone, he braced himself against the counter, fingers curling around the edge of the sink, and closed his eyes.

"Cas?"

It was weird, he could admit, having another presence in his head. Cas was keeping pretty quiet, but Dean could still feel him. Whether that was out of that misguided feeling of being a burden or because he was still tired and healing, the hunter wasn't sure. Probably both, knowing their angel. But he knew, even with the silence in his head, that Cas was still there. It presented almost like a gut instinct in the middle of a hunt; he could feel the angel, sense him just on the periphery. Whether it was fleeting emotions, swells of thought that he was pretty sure weren't his, or the comforting warmth in his chest that had to be the angel.

Well, that, or an oncoming heart attack. He'd certainly eaten his fair share of cheeseburgers in his lifetime.

 _"I'm here, Dean."_

The hunter let out a slow breath and opened his eyes. Straightening, he made for the fridge. Speaking of heart attacks; he'd told Sam he'd be cooking up dinner and he had every intention of doing so, even if the guise of it had really been an excuse to speak to Cas in private. Dean moved on autopilot as he pulled out a couple of steaks and some of Sam's rabbit food.

"How are you feeling – really?"

 _"I'm very tired_." The honest reply came after only a second of hesitation. Dean knew Cas had considered telling him he was fine, and not because he was in the guy's head as much as Cas was in his, but because he just knew the angel that well.

He sounded tired, too. Cas had put on a brave front while talking to Sam earlier, not that the younger Winchester could see or hear him. But he'd done so regardless, and Dean hadn't bothered mentioning it to Sam. Kind of a low blow to call the angel out on something he couldn't hide from the guy serving as his vessel.

"Yeah, I figured. Well, rest up and take all the time you need, buddy." Dean pulled out a skillet and cutting board. He flipped on the stove and starting chopping up the greens.

 _"Thank you for offering yourself to save me, Dean. Surrendering your body is a sacrifice I can never begin to repay, and I-"_

"Whoa, Cas, enough," Dean cut the angel off, knife stilling against the board. He fought the blush rising to his cheeks and instead focused on not taking a finger off with how tense he suddenly was. "It's no biggie, alright?"

 _Unless Sam was right_ , he thought absently and with a little more bitterness than he ever would have let Cas hear. _Then I'm apparently serving as your own personal prison, and that would be a biggie, damn it_.

He almost sliced the tip of his pointer clear off (thank god for fingernails), his muscles suddenly even more tense, before Dean realized it wasn't him doing it. It took another moment to realize _why_ Cas was tensing them up, and he choked on the sudden lump in his throat that tasted a lot like dread.

"You heard that, didn't you?" Dean tipped his head back with a defeated sigh and let the knife clatter atop the cutting board. "You can hear all my thoughts."

It wasn't a question, and Cas didn't answer it – not directly. But the guilty silence and flood of discomfort was telling enough. Dean lowered his head back down, chin damn near his chest, as he breathed in deep.

God damn it, Sam hadn't just been right, he'd been _very_ right. Dean hadn't thought this through. How the hell was he going to live with Cas in his head, hearing his every thought? He wasn't a _nice_ person in his head. Hell, he wasn't even a good person, and his only saving grace was that he usually kept most of that shit to himself, unless he was drunk. Or angry.

 _"You are a good person, Dean_ ," Cas insisted, though considering the source material he was answering had been an unspoken thought Dean would have never let him hear aloud, the angel wasn't really helping either of their cases. _"I am sorry for this situation. I promise, with Sam's help, we will remedy it as soon as possible-"_

"It's fine, Cas," Dean answered by rote, wincing when they both realized how untrue it was at the same time. He groaned aloud, since it was pointless not to. "Okay, so _fine_ isn't exactly the right word but… It's better than you being dead."

And that was the truth. Cas could read his friggin' head if he doubted it. Not that the angel did, from the swell of warmth and devotion that felt a hell of a lot like love that Dean got in response.

"We'll work it out, alright? And until then…" Dean shrugged, picking the knife back up. "I don't know. We'll figure it out, I guess."

 _"We will do what we always do; get through it together_. _"_ That time Cas sounded a little more like himself and Dean chuckled at how literal it would be this time. The tension eased, and the hunter and angel went back to making dinner.


	4. Chapter 4

**_Summary:_** _It's a split second choice - probably the only one they have left. But Dean makes it, because it's Cas lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU_

 ** _A/N_** _: I am apparently incapable of updating this story on a weekly basis, it would seem. Mind you, Real Life is insane right now with my job trying to kill me via sleep deprivation and stress, but still. I mean, it's already written, all I have to do is remember to post it . One day. One week. I'll get there. I'll be *that* author._

 _Thanks for all the favs/follows and comments, and hello to the new folk reading just now! Hope you all enjoy my favorite chapter of this story :D_

-o-o-o-o-o-o-o-o-

 **Cohabitation**

Chapter 4

-o-o-o-o-o-o-o-o-

They spent the rest of the week working on the spell. Dean slept through a lot of it once he and Sam were finally able to convince Cas to take control. For practical reasons, was the excuse Sam finally won out with. Dean as the middle man left too much room for error on something as delicate and precise as spell crafting. Especially something as powerful as a golem.

Still, it had included a lot of anger and yelling between the two, Sam was pretty certain, if Cas's guilty demeanor quickly hardening into stoic, solder-like efficiency once he was in control was any hint at how that internal argument had really gone. Sam needed to separate them. Both were too emotionally repressed, guilt-driven martyrs with years of baggage on their backs to ever survive being in each other's heads. Being able to keep their thoughts their own was something that made the three of them functional as a family. The two had needed a heart-to-heart for years now, but they needed it face-to-face, where they could still save some secrets and some emotions from one another. Where they could still feel some things were theirs to keep, theirs to control.

Sam knew what it was like to lose that control, and he knew his two brothers, his best friends, would need it back, and soon.

So Cas took over and Dean slept better than he'd ever slept as just a human, something he hadn't been expecting and Sam was surprised to hear. It certainly hadn't been that way with Lucifer. Although, looking back on it, he supposed it could have been with Gadreel. He had been healing during that time, and when he was awake he didn't recall feeling as tired as he should have, given what it was he was healing from. But Dean swore it was some of the best rest he'd ever had. A couple hours felt like a full night's sleep each time. And not the four hours he was used to, but a full eight. Hell, maybe even ten or twelve (not that he actually knew what that felt like unless it was a crash from an injury or one hell of a bender).

Considering Sam was only averaging about four himself each night, what with all the spell work, research, and most recently _sculpting_ he was trying to get done, he couldn't help but be a little jealous. And as soon as Dean picked up on that, Cas knew about it, which meant the angel was both insisting on small bouts of healing every day now _and_ lecturing him on how he needed to rest more. Turns out, Dean and Cas weren't the only ones who were going to suffer consequences of this new merger.

But back to the sculpting. Because it was their first real problem, it turned out. It hadn't taken long (less than a day, actually) for the brothers to realize that they didn't have an artistic bone between them. Unless you counted drawing sigils, and even then, Cas quietly confirmed that their workmanship actually left a lot to be desired.

' _Gee, thanks, Cas_ ,' had been Dean's sarcastic reply, to which the angel awkwardly and apologetically shrugged. It was the truth, as far as angel standards went.

Once they settled on the golem plan, Sam ordered two hundred pounds of clay to start with after extensive research across multiple artists' blogs and clay production websites. Dean flat-out _balked_ at the amount of clay that showed up on at the bunker. And they'd had to tip the delivery guy some serious pocket change to get him to carry it down into the library (and then even _more_ money to keep from him from asking any questions).

His punk little brother used the excuse of not wanting loading the Impala down with that much excess weight ( _'_ _ **Wet**_ _weight, Dean. Clay's kinda, you know, messy.')_ but Dean was a hundred percent sure Sam was using his weakness for his Baby as an excuse to get out of hauling two hundred friggin' pounds into and out of a car and into and out of the bunker because he knew he'd friggin' win with it.

And he had, damnit.

Dean was still grumbling about it (Castiel's internal guilt about the money spent was _not_ helping) as Sam explained that they could have done with less clay if they'd be able to use a rebar or wood as a support structure inside the sculpture (apparently called an armature, according to his giant nerd of a brother), but they couldn't do that in this case. Golems had to be entirely made out of clay. Any internal support of another material would weaken the spell and the integrity of the golem's body once created. So there they had it.

Still. A couple hundred dollars later in clay (and a couple hundred more in friggin' delivery fees and bribery) and they discovered the real hurdle. It wasn't stairs or wet weight or loud-mouthed delivery men.

Neither Winchester man could sculpt worth half a damn.

Sam gave it the first try, but it was pretty obvious after he'd gotten the basic shape of a human down that he had no artistic talent when it came to sculpting. He was halfway decent at a drawing now and then, but trees, symbols, things he'd seen. And though he'd spent plenty of the last eight years around Cas, his talents ended when it came to drawing the human face. And carving it was a different matter completely.

Dean, still grumbling and insisting this was a waste of time, gave it a shot as well and his attempt had turned out worse. He managed to slice off half of the face Sam had got going with a little scalpel mishap. Sam didn't even know how he'd managed to do it (' _Why were you using a scalpel to start with!? It's a sculpture, not an autopsy!'_ ) and had promptly kicked his older brother out of the library where they'd set up shop.

Dean left with a hollered, 'Told you so!' that was entirely as unhelpful as the rest of him had been.

So, Sam was back to researching until he found an artist local enough to drive to them and desperate enough to work under some pretty weird conditions. Turns out, art school was _expensive_ and there were several students in the state of Kansas ready to sign up for a no-questions-asked sculpting gig if it got them paid. Sam settled on a young woman a couple of towns away who had an impressive portfolio, a relatively low hourly rate, and four years of student debts to pay off. He met her in downtown Lebanon at a café for some neutral ground, explained what he needed and had her sign a completely bogus nondisclosure agreement he'd whipped up to make him and Dean look like some trust-fund babies with some serious money and some even more serious privacy issues.

The artist agreed with only the occasional weird look, and Sam had her follow him back to the bunker. The weird looks continued, but she didn't say anything more than to warn them she had pepper spray in her bag in case this was some sort of freaky abduction, sex-slave-in-the-underground-apocalypse-bunker sorta thing. Sam laughed awkwardly, Dean just smirked all tight-lipped, and Sam promptly moved them on.

Dean handed her a photo of Cas – the same one they'd used for his FBI badge – and another of his full frame, from the time he'd gone Godstiel on them and CCTV had captured him on camera murdering a bunch of people. The Winchesters were kinda hoping this kid was a tad too young to have been watching the news at that time.

(They really should have taken at least one photo with the guy over the last eight years. At least, one they hadn't burned.)

Lucky for them, she didn't recognize either photo, and pretty much got to work with no questions asked. Sam showed her the nearest bathroom, the kitchen, and even a room she could crash in if she wanted to sleep there. Not that she had to, he quickly added when she gave him that look that he was pretty sure was her rendition of sizing him up for serial killer material. It was there if she needed it, otherwise come and go as she pleased, so long as she didn't bring any attention to their home or tell anyone where she was or what she was doing.

"I'm pretty sure that's what the NDA was for," she'd replied dryly before heading back to the library and the pile of half-formed clay. Sam followed along awkwardly, settling himself at the table to resume his research (though, far enough away from her little workshop so the book titles weren't readable and he could pull out some normal reading material as cover if she wandered over).

He watched her on and off (still awkwardly) for the first couple of hours, but the woman seemed genuinely intent in her work ad serious about that no-questions stuff. So Sam went back to tweaking the spell, grabbing Cas when Dean wandered back in a couple hours later, and the two settled into spell crafting with their artist working on his visage in the corner.

-o-o-o-

It took three days, but their artist created a pretty damn good look alike. It cost them another several hundred dollars – half a friggin' fortune, Dean grumbled at that point – by the time she was done. Which had Dean continuously muttering _'stop apologizing'_ aloud to himself over and over again. But by that third day they had a clay figure with an uncanny likeness to Cas.

"That's just…freaky," Dean said as they stood in front of the life-size sculpture, having escorted the woman out of the bunker with her handful of cash. Sam glanced over at him, and he could practically see the head tilt Cas was making somewhere inside Dean's head.

"She did a really good job," he agreed, staring at the colorless rendition of their friend. "It should be enough to pass as human once we get the spell attached. Speaking of."

Sam went over to the end of the library table and snatched a small scroll of the table, rolling it up into a tube as he headed back over. He'd spent the whole night writing the spell out on the thin, long sheet of parchment they'd had to purchase specially for the spell. Cas had stayed up with him, occasionally staring wide-eyed from Dean's face at the artist putting the finishing touches on, well, himself.

Man, the look that woman had given them when they'd asked her to sculpt their friend with an open mouth, tongue up, was…well, even Sam had blushed and it had gotten awkward.

"We gotta ask her to do _what_?" Dean had practically choked on his scrambled eggs when Sam first brought it up. Then again, maybe he should have known better than to bring it up over breakfast.

"That's where you put the scroll to make a golem, Dean," the younger Winchester explained, exasperated. "Under the tongue."

An absolute _fortune_. That was what a no-questions-asked, under-some-weird-ass-conditions, am-I-making-you-some-fucked-up-sex-toy-made-out-of- _clay?,_ sculpture cost these days. Dean just muttered more and sharply told himself to apologizing, it wasn't his fault.

Yeah, the woman they'd hired had taken to avoiding Dean since day one.

With a deep breath and a hopeful glance at his brother, Sam stepped up to the clay sculpture and slipped the scroll beneath the carved tongue. Given his height over the Cas-look-alike, Sam saw the scripture light with shimmering red power, the words glowing like embers. That light quickly spread throughout the clay figure, and the words Sam had written on the parchment appeared across every inch of the clay, lit with the same waves of red.

They faded as the grey of the clay started to fade into other colors – fleshy pinks and tans and blues and blacks that filled out the sculpted trenchcoat, suit, tie, skin and hair. As the last of the grey disappeared for realistic looking skin and fiber, the sculpture's eyes snapped open a fierce blue and Sam and Dean took a surprised step back at the sudden movement, the older going for the gun tucked into the back of his pants.

But Clay-Cas didn't move further. There was life there, of a sort, as it stood still, non-moving, non-blinking, but…fleshy.

"Okay, that's creepier." Dean released the butt of his gun slowly. It took a couple of minutes before he was convinced the thing wasn't going to attack them, or move at all (he probably would shoot it if it did out of pure horror-movie survival principles). The way not-Cas just stood there, staring, reminded him too much of Cas under Naomi's control. He was not a fan.

Which, of course, Cas picked up on and Dean could feel the responding guilt, shame, and self-loathing. Neither of them had said a single thing, but now Cas was miserable and Dean was frustrated because it wasn't Cas's fault – either then or now – and he never _meant_ to bring it up.

Sam was right. This was going to drive them both into an early grave.

"It should be less creepy once we get Cas inside." Sam turned towards the angel/brother duo with a grimace that was probably supposed to be an encouraging smile. "Time for the last ingredient."

And the part all parties were looking forward to the absolute least.

 _'You should get some sleep first, Sam_ ,' Cas spoke up from within Dean, trying to push his own mixed emotions and trepidation aside at the memories that grace extractor always brought up. Memories he could mostly keep from Dean as an angel possessing a vessel, but feelings seemed to slip right through in his drastically weakened state as an angel with barely any grace left to wedge between him and his human charge.

Dean relayed the message and, though Sam seemed hesitant and it took several convincing arguments, the younger Winchester reluctantly agreed. So they left the creepy-ass, life-like Cas just hanging out in the corner of the library (Dean did not trust it and would certainly be sleeping with a gun under his pillow tonight) and headed for the dormitory wing for a couple hours rest before the big event.

-o-o-o-

The next morning, with both humans refreshed and feeling at least halfway decent (Sam with the hope of freeing both his brothers, Dean who was honestly starting to lose his mind, and Cas who was very much done with feeling nothing but feelings over the last week and a half) headed down to extract Cas's grace from Dean's body. Sam strapped Dean down onto the infirmary chair quietly, stewing in his own unpleasant memories of how much this would hurt. He set the box with the oversized needle on the tray beside the chair and braced himself for what he was about to do.

"Just get it over with, Sammy," Dean griped, not liking the air of trepidation that was all around him (and inside him thanks to his resident angel). "Like ripping off a band-aid."

He regretted those words the minute Sam pulled the syringe out of its case. That was one hell of a band-aid.

Dean's fingers dug into the armrests of the chair as tension filled him that was mostly not his own, but he grit his teeth and kept quiet. He was doing this for Cas. Cas and his own sanity, but mostly Cas. He could feel the angel's own trepidation, and Dean forced himself to relax, telling Cas to do the same. Tensing was going to make it worse.

Sam took a deep breath, lining the syringe up with his neck, just below his ear. With a deep breath and a last word of advice – "Try not to move" – he started the slow descent of the needle into his brother's skin.

The pinch hurt, as did having a friggin' needle the size of a damn straw stuck into his skin. Dean grit his teeth through it, but overall thought, _'This isn't so bad.'_

Unfortunately, he heard Cas's unintendedly voiced, _'Just wait,'_ right at the same time Sam settled the needle in as far as it needed to go.

"Okay," his brother breathed out, the shakiness in his voice an outlet for his rock-steady hands. "Here we go."

Then he started to pull the plunger back and Dean's grip into the chair became white-knuckled, then shaking-knuckled, and then shaking-the-entire-armrest, as fire erupted in his neck and through his body like white-hot blades. He could feel it down to his toes – every inch of him – sucking the very life out of veins (and the air and the muscle and the tissue and everything that made up everything he was and suddenly Dean understood how every character ever sucked out into space through a hole in a spaceship felt) as Sam started to extract Cas's grace from his body.

Flickering white-blue light spurted into the syringe in little sputters, and Sam had to fight back the disheartenment at how weak and grey that once powerful light now was. It sputtered in the syringe, more filling the glass container than he remembered with Gadreel, but still less than a fourth of what the cylinder could hold.

"S-Sam-" Dean's voice through his gritted teeth and compressed jaw was raw with pain. He could barely breath, and he could feel how much worse it was for the angel inside him.

Sam ground his own jaw as he kept pulling at the plunger. "Almost there, Dean."

"N-No," his brother sputtered. His fingernails were staring to bleed with how hard he was holding onto the chair and he would have bruises from the restraints. "You g-gotta st-stop."

"I've almost got it!" Sam pulled the plunger a little faster, seeing the first specks of red blood enter the syringe with the trail end of the grace.

"Sam, st-stop!" his brother practically screamed, arching his back. "It's- It's killing him!"

The younger Winchester fumbled the syringe as he let go of the plunger, heart hammering in his chest. It took every ounce of his self-control not to withdraw the needle or let his hands shake as desperately as they wanted – needed – to. "Dean?"

Still arched across the chair, his brother was heaving with uncontrolled pain. "You gotta put it back," he moaned, eyes mere slits that pleaded with his brother. "It's k-killing him, Sammy."

"I'm almost there, Dean," he whispered – pleaded – back, eyes darting between the syringe of glowing light and his brother's ashen face.

Dean shook his head the best he could, neck muscles bulging in agony and veins throbbing in his face and throat. He could take the pain, but he couldn't take hearing his friend screaming inside his head. There was no barrier between them, no way to muffle his pain, and Dean knew to his very core that if they continued, Cas wouldn't survive it.

"We'll f-find another way."

The younger Winchester fought back the overwhelming urge to just finish it, to rescue their angel and free his brother, but he couldn't do it. Sam trusted his brother. Even being so close, even knowing one more pull and he'd have all of Cas, he couldn't do it. He knew Dean; pain wouldn't make his brother stop. But Cas's pain – Cas dying – would.

Sam breathed out pure defeat and he couldn't keep his hands from shaking, but he nodded roughly and started to push the plunger back in. Dean couldn't quiet the scream that finally tore out of his throat as that fire re-entered his system, ragged and torn on the edges, ripping it's way through his body with nothing to dampen the pure power and savage pain of another's essence overtaking his body.

The last of the grace vanished as Sam fully depressed the plunger and Dean's eyes lit blue with the completion of the possession, even as a second scream tore from his throat. The lights above them burst, sending sparks and shards of glass raining down on them. Castiel's grace lit the room in a flash of blue-white before everything fell silent.

Sam couldn't contain the broken sob that ripped at his own throat or his panic as Dean lay completely limp and, for several terrifying seconds, Sam had no idea if he'd just killed both his brothers.

-o-o-o-

Dean woke up after only a couple of hours. The first of which Sam had sat glued to his brother's bedside (after he'd manhandled the dead-weight of his still-breathing body through the bunker and back to his room) worried he might slip away if Sam wasn't watching. The last several Sam had spent certain that Dean would live but terrified that he'd killed Cas. He had no way of knowing if the angel was still there, and had to tell himself over and over again that there would have been wing prints.

Only, Cas didn't have wings anymore.

He spent those hours alternating between trying to find out where they went wrong, what they could do now, searching for a spell to detect an angel inside a vessel, triple checking the infirmary for charcoal prints of any kind, and sitting in his brother's room watching the rise and fall of his chest with half the library in there with them. Dean would be pissed at the mess of books in his room when he woke up and Sam would welcome it when it happened.

When Dean did finally come to, it was with a hoarse voice and a sore throat. But given his little brother's faintly red-ringed eyes, utter lack of rest, and clear worry, he quickly reported that he and Cas were both okay.

"What happened?" Sam asked roughly, closing the thin and only manual they had on the grace extractor, written damn near a hundred years ago and all but buried in the bunker's archives. And also pretty damn useless.

Dean just shook his head, blinking away the raw emotion and memory of those screams. God, he never wanted to hear Cas like that ever again. But, while the angel was weak and sounded small in his head, he was still answering Sam's question. "He says his grace was too weak. The pull from the syringe was tearing-" Dean cut himself off, swallowing through a lump of pain that was and wasn't his, "-tearing it in half."

Sam looked as nauseous as he felt, but Dean reassured him again that Cas was okay now.

"What do we do now?" His little brother's voice sounded young, and Dean was reminded that even at thirty-something, Sam was, in all the ways that mattered to Dean, still just a kid sometimes. A kid who was terrified for his brother and his best friend, and had wielded the thing that nearly killed them both, even if it wasn't his fault.

Truth be told, Dean was just as lost and just as worried about it. He hadn't really let himself think about what came next if this didn't work, because it was going to work. It _had_ to work. It was becoming clearer every day that he and Cas might make decent roommates, but they were not gonna work out as head buddies. Dean needed his… well, space. And Cas…god, Cas was carrying around just as much damn guilt and hurt as Dean, and the hunter had already been on that precarious edge of having as much of that shit as he could handle on his own. Together, it was a straight up martyr fest of misery in there right now.

Dean snorted internally. What a pair they made.

 _'Indeed_ ,' Cas agreed, his voice as wry and bitter as it was endearing and amused. A perfect match to Dean's own mood.

"We'll figure this out," Dean said aloud, because he meant it for the angel, but he also meant it for his own brother. Because they would. Yeah, this was going to suck, but they'd make it work. Really make it work, not just tough it out until they found a solution, because as terrifying as it was, Dean and Cas were both realizing that there might not _be_ a solution.

Did he mention that was terrifying as all getout?

But he'd be damned if he was going to let Sam see any of that. Or his angel (well, more than what was already on the table because they shared a friggin' body and he couldn't hide anything.) So he pulled on his big brother face, set in stone and determination, and told them both that they'd figure this out. "We'll give Cas a chance to heal his grace," he offered, knowing what that meant for both of them. "Maybe when he's stronger, we try again. Or maybe we call in a favor."

They had enough of those that someone ought to be able to help. Hell, worse case they bring in Crowley or Rowena. Dean was reluctant as hell to work with either of those two, but both had proven useful and for Cas's life, any price would be worth it.

Cas seemed far less sure, but Dean just sent more of that big-brother determination towards the angel in solid waves of 'shut up and listen to me' that seemed to amuse the angel as much as it consternated him. Still, amusement was something the hunter would take over guilt or pain any day, so he went with it.

Sam settled back in the chair he'd dragged in from the library. He looked as torn as Castiel felt, but he offered up a weak smile to his two brothers. "Alright. I'll um…I'll make some calls."

"Tomorrow, Sammy." Dean sagged back into the bed, realizing just how exhausted he was even after the forced unconsciousness. "Right now, I call timeout for a breather."

When Sam nodded way too readily, standing and starting to gather books into his arms (and _Jesus_ , did the kid bring the entire bunker archives into his bedroom?!), Dean frowned. "That means you too. Don't think I can't see those bags under your eyes. So sit your ass back down or go to bed, but no more research."

He angled a look at his kid brother that might have been demanding but was also knowing. It promised a return to the books tomorrow, without complaint even, but rest for today.

Sam's gigantor shoulders sagged, but he lowered the books back into their piles and all but collapsed back into the chair. Dean had a point, even if Sam was dealing with his own fair share of guilt and driving need to fix this. And his brother looked about ready to pass out, and Sam knew he would climb his exhausted butt out of that bed and force Sam into his own if he didn't just agree, so that's what Sam did. He agreed, and he spent the next several hours watching over both his brothers before finally crawling off to catch a few hours of rest himself.

(With maybe just one bunker book in hand. In case he couldn't sleep, of course.)


	5. Chapter 5

**_Summary:_** _It's a split second choice - probably the only one they have left. But Dean makes it, because it's Cas lying there, bound and beaten, with a bomb strapped to his chest counting down all their deaths. How bad could it be, saying yes to an angel? Season 12 AU_

 ** _A/N_** _: So this marks the end of the official story. There will be one more chapter after this that is an epilogue of sorts. Thanks to all who've read, followed/faved, and commented!_

-o-o-o-o-o-o-o-o-

 **Cohabitation**

Chapter 5

-o-o-o-o-o-o-o-o-

In the end, they did call Crowley in. It took another week of rest to talk Cas into it, what with the angel being very reluctant to get in bed with the demon once again, but Sam and Dean had worked with him several times more recently than Cas had, and felt at least alright about calling the King of Hell for a favor. Granted, they hadn't royally screwed him six years ago but…well, Dean had gone demon-dear-john on him and Sam had definitely tried to kill him at least once during that fiasco (and vice versa), so it wasn't like any of them were perfect.

But, in the last two years he'd put his own hide on the chopping block trying to help Cas evict Lucifer (which may have been more about saving his own skin against the devil than saving Cas, but, eh, he _was_ a demon, after all). And he had saved Cas's life when he'd been a sure-goner against Ramiel and his spear. So, at least currently, the King of Hell was on Dean's good side. As much as a king of hell could be.

"Well, well, isn't this ironic." Crowley was staring at Dean with way too much amusement, as the hunter's face switched from Dean's deadpan glare to Cas's exact same deadpan glare. Sam hadn't even noticed there was a switch to see, but to the demon it was clear as day and funny as hell. "All that talk about destiny and saying no, and it finally happens because your pet angel needs a transfusion. Oh, if only Heaven had known one little bomb was all it would take."

"Stow it, Crowley," Dean snapped, crossing his arms over his chest both defensively and protectively. "Can you help or not?"

"Not," Crowley conceded with hardly an apologetic tone, though he did tilt his head towards them in some sort of acknowledgement. When Dean's look hardened, the king of Hell shrugged, and that at least did seem conciliatory. "Sorry, boys, your kitten's too banged up. The years have not been kind to that tattered ball of grace, and that I can't change. He may strengthen over time, but there's nothing I can do to help it along. Only another angel could."

 _'No_ ,' Cas growled so fiercely that Dean physically frowned. He didn't have to ask; flashes of memory of Crowley standing over him, a vial of white light in his hand, and another brother's death on his conscience, was all Dean needed to understand what it was the demon was suggesting. And…yeah, okay, he wasn't exactly a fan of the majority of angels out there, but he could see where Cas was coming from, refusing to murder another of his brothers to prolong his own life.

Not to mention, Dean was really not up for adding a third party crasher to this little sharing-shindig they had going on. Two was one too many already.

When Dean said as much, Cas's voice backing his own, Crowley just shrugged again. "For the best, probably. Even that would be a temporary fix, at most. It _might_ get kitten out of his squirrel-shaped shell, but it's entirely possible the additional grace would fight for control as soon as it was outside the buffer of a vessel. And with how weak our little angel is, I wouldn't put betting odds on him. Sorry, boys, your options are nil."

Sam let out a bone-weary sigh, and Dean scrubbed his fingers through his hair. Alright, well, it had always been a long shot to start with. They were just back to plan A: figure it out the hard way.

"This, though." Crowley's face lit with delight as he turned away from the two hunters and gestured with open arms at the golem. The Cas look-alike still stood there, blue eyes open wide but registering nothing. Crowley clucked his tongue cheerfully. " _This_ I could have fun with."

Dean slapped his hand away before he could poke the arm of the golem, giving him a look that promised pain. Crowley backed off, hands raised, and told the hunter he was absolutely no fun at all.

"So, there's nothing?" Sam asked, trying one last attempt to both refocus them and dig into Crowley's near limitless resources. But the demon just shrugged his black-clad shoulders.

"Maybe with a soul deal-"

All three of them said no at once, Dean's and Cas's coming out as a weird mix of both their voices. Crowley looked amused and insulted at the same time, but ultimately just clucked his tongue again.

"Well, then, not my monkeys and all that." The demon cast one last amused glance at the stock-still golem before he headed for exit, hands in his pockets. "Call me if something changes. Including your minds."

The bunker door slammed shut behind him, and Sam and Dean exchanged a glance between them. Time to cover all their bases and call Rowena, make sure Crowley hadn't missed – or purposefully omitted – any options.

-o-o-o-

"Sorry, lads, but there's not much _I_ can do. I'm just a humble witch, after all."

Dean snorted at the phone, open on the table and set on speaker, but he didn't think Rowena was actually lying. Blowing smoke out of her ass, absolutely, but she probably didn't have an option for helping them out. Otherwise she'd be talking price.

"Alright, thanks, Rowena." Sam, the far more diplomatic of the two, reached across the table and hit the end button. Dean gripped the back of the chair he was leaning on top of and sighed in frustration. Sam spared him a worried, sympathetic look. "We'll figure something else out."

"Maybe we won't." Dean rubbed at his tightly clenched eyes, fighting off the irritation and the headache that came with it. At his brother's glance – worried he was giving up – Dean tossed his arms out. "Maybe this is how it is. Cas is stuck in here and I-" he sighed. He might not have known what he was signing up for when he'd said yes, but he wouldn't take it back. Cas was _alive_ , and that was worth a million years of having no privacy or secrets. "I can figure out how to make that work."

Sam could hear Dean's unspoken words, and Cas didn't need the younger Winchester's years of experience to interpret what Dean didn't say. Not anymore.

"Okay." The younger Winchester took a deep breath and offered an encouraging smile. Because he believed in those two, more than he believed in anyone else in his life. They would figure it out because they had to, and he would be there for them along the (undoubtedly rocky) way. "Okay. I'm not giving up, but we'll figure it out. Either way. It'll be okay."

"Yeah," Dean tried to believe it. It helped that the angel inside his head was bolstering them with his own confidence, even if it was as shaky as Dean's. Still, it was twice the confidence he'd have had otherwise. "It will."

-o-o-o-

They agreed to move Cas's golem to the dungeon after the unanimous decision that it couldn't stay in the library and it was way too creepy to keep activated. Sam, in a stroke of absolute genius, halted Dean before he could remove the scroll.

"Wait, we should move him first." Green eyes blinked his way, hand already inside the golem's now open-mouth (and oh, but did Sam wish he had a camera. Because the golem, for all intent and purposes, sure looked like Cas). "We should be able to tell him to follow us to the dungeon. Then we can take the scroll out."

As Dean glanced between his brother and the golem, Sam shrugged self-consciously. "It'll be easier than figuring out how to move two hundred pounds of hardened clay."

Dean pulled his hand out of Golem-Cas's mouth like he'd been electrocuted and told his brother he was a genius. They hadn't exactly had the woman sculpt the Cas-look-alike on anything but a wooden palate covered in now-clay-soaked canvas.

Sam stepped in front of the Golem, nerves a little jittery (this was the first golem they had ever made, and the legends did have a tendency of going not-so-well for the creators) and took a deep breath.

"Follow us," he commanded and the golem shifted his head ever so slightly to stare directly at Sam. Without a 'soul' (which was really just clever spellwork) or Cas's grace in there, the golem probably couldn't talk; it was the equivalent of him not having a brain, only basic programing. Still, as Sam took a few deliberate steps back, the golem followed, shuffling forward with a great weight that didn't match Cas's lithe frame.

"Awesome," Dean muttered, his voice caught between actually finding this cool and finding it incredibly creepy. "He's not gonna murder us in our sleep at all."

' _Especially not after saying it aloud for him to hear,'_ Cas added, oh-so-helpfully, and Dean grumbled to him to shut the hell up.

Sam turned and headed out of the dungeon, the golem following while Dean pulled up the rear. He was armed and ready to hunt this thing down if it so much as moved wrong, but Golem-Cas just followed after Sam quietly as they escorted it through the bunker and down to the dungeon. Sam instructed it to stand in the corner, which it did without question, and then open its mouth.

Pulling the scroll out immediately triggered the red wave of words to wash over Golem-Cas's skin once more. Similar to its creation, the words faded and with them all the color and life from skin and fabric until only grey clay remained.

Dean poked the thing's arm, but his finger encountered only hardened, slightly tacky clay and he gave Sam a, _'maybe this is okay?'_ look.

"It's still creepy," he grumbled, turning and heading out of the dungeon. Sam shook his head, placing the scroll on the nearest surface and following his brothers out. They shut the trick bookcase doors and Dean went ahead and locked them up right because he could and there was no way he was sleeping in the bunker with a creepy non-living statue of Cas hanging out in the dungeon unattended. So lock it was.

And maybe – hopefully – they'd be back for it in a couple of weeks or a month or two once Cas strengthened up.

-o-o-o-

It was longer than that, time passing without any new ideas, new solutions or spells, or anything to help Cas get back to a body of his own. It wasn't so much that Sam was losing hope as it was that he was increasingly disappointed in himself for not having found a way out for his two brothers. He'd been so sure he could solve this for them.

They, on the other hand, seemed to be going the opposite direction of settling right down into this. Dean, particularly. The caretaker personality of the three of them, he put on his super hero cape (made mostly out of guilt and weighing a metric ton) and brute forced his way through. Which mean, yeah, a whole ton of ugly and misunderstandings, but Sam supposed one good thing to come out of sharing head space with someone was that misunderstandings couldn't last very long. It was hard to not be on the same page when you could hear each other reading that page aloud.

But Dean was trying. Trying to be less aggravated at having no space when it came to his best friend (he ultimately decided that a lack of mental space wasn't so different from having no personal space, and he'd gotten over that eventually, hadn't he?). The lack of privacy still rankled Dean more than anything else, and the over-abundance of emotion he could neither block on the incoming or hide on the outgoing was a constant source of drainage on Cas. But they were learning. Dean was learning not to have so many miscommunications or accidental triggerings of every guilt ridden memory either of them had ever had. That was a bit more of a struggle for them, which just drove home all the more how emotionally inhibited the two of them really were (which meant admitting Sam was right, which Dean _hated_ doing). He also spent a not insignificant amount of his allotted patience (of which, he could admit, there wasn't as much as there should be), trying to push Cas to the forefront for at least a quarter of the time he spent awake, and insisting the angel could have the four hours that he regularly slept through the night, since he seemed to sleep anyway whether or not the angel took his body for a stroll.

Cas was slower to go all in, particularly on that last one. Despite Dean's first reassurance, then aggravated re-reassurance, and finally all-out irritation because assurances (no matter the number of "re"s in front) just weren't cutting it, Castiel was adamant that he not impede on Dean's free will (Dean's translation: stubborn, mule-headed, standoffish, jerk just to be a jerk- you get the idea). Even if that free will _was_ to offer his body for the angel's use. Which, after about a week of cycling between "you can impede Cas, I'm asking you to impede" and "no, you don't really want me to", the hunter had finally exploded in all-out epic shouting match which he, of course, couldn't keep inside his head (he wasn't very good about keeping his thoughts in his head on the average day, let alone when he was having an actual conversation with someone, let alone let alone when he was having an argument with that someone). So Sam got woken up from a dead sleep by a one-sided argument that had him racing into the library, gun drawn.

Which was, apparently, enough to finally convince Cas that not taking his fair share of the physical control over Dean's body was causing more harm than good.

 _Finally_. Sheesh.

Things had calmed down a bit since that day. Castiel was still shy about taking the reins, but his confidence grew each week that their tentative understanding with one another didn't shatter and Dean really didn't seem to mind (well, most of the time. There were still occasions, but the important thing was that they were learning to work through those). Dean took the majority of the driver's seat most days, but he was learning to hand over control on a more regular basis and Cas was slowly starting to take the wheel, even doing so on more spontaneous occasions, with less guilt and obligation.

Sam walked into the kitchen three months after they'd almost lost Cas to that bomb, to find the angel in his brother's body _cooking_. He knew it was Cas because he always held himself stiff and rigid. Dean was a loose goose compared to when the angel was in control, and he'd complained on multiple occasions how his back muscles hurt from standing so friggin upright hours on end. Sam mostly ignored all of those times, since better posture was a _good_ thing.

"Morning, Cas," he greeted as he crossed the room and headed for the coffee. His role in all of this had been to act completely normal anytime Cas was in control.

"Good morning, Sam." Cas's focus was entirely on the slowly cooking eggs, spatula at the ready. Sam wanted to laugh at how serious he looked, but refrained.

"Yeah, morning sunshine."

Sam blinked as Dean's voice returned to normal from the deeper tone it always took when Cas was the one speaking. His posture didn't change from the statue-like rigidity Cas held. Pleasant surprise pooled in Sam's gut as he realized the two of them really were getting better at sharing.

"Is Dean teaching you how to cook?" Not that Cas hadn't tried on previous occasions, but microwaving a burrito was about as masterful as the poor guy had ever gotten. And Dean had gone through several fire extinguishers and a couple smoke alarms before finally calling it quits on teaching him.

"I suggested having breakfast and coffee prepared for when he woke up," Cas answered, voice switching back to the deep, gravely version that had frankly been so weird to hear those first couple weeks. "It was apparently incentive enough to try teaching me again."

"I was hoping there'd be muscle memory or something," Dean said, voice switching back. This time his body followed through, loosening as he turned to look at Sam, waving the spatula about in a much more animated (much more _Dean_ ) way. "Not so much. This is our third try."

He pointed the spatula down at the eggs with a sardonic look, which shifted quickly into the more stoic planes of Cas's control.

"The first was not entirely my fault."

"I told you _medium_ heat."

"I turned it to medium heat."

"Yeah, well, you can't trust what the stove says, you have to gauge it yourself."

"Information that would have been helpful before the eggs were burning."

Sam's laughter interrupted their conversation which was, to be honest, utterly dizzying but also highly entertaining. He couldn't help it; the worry that had been building for months and only slowly ebbing away with each not-totally-disastrous encounter like this, finally let go of his gut completely. For the first time in months, Sam thought maybe they'd actually get through this.

"It is good to hear you laugh, Sam."

The younger Winchester bit back the last of his chuckles, sobering somewhat at the sincerity in Cas's voice. Sam offered a smile, though it was a heavier one than he'd meant. It was true, wasn't it, that he'd spent so much time worrying about the two of them that he'd probably stopped taking such good care of himself.

"Did you want to braid his hair next, Cas?"

Sam bit back another chuckle as his brother grumbled under his breath about sleepovers and heart-to-hearts, but he could see the slight warmth to Dean's cheeks and knew the good natured muttering was his older brother's way of expressing exactly what Cas had put into actual words.

"Thanks, Cas," he said, a little emphasis on the angel's name just to rub it in. Sure enough, Dean grumbled more. "It feels good to laugh."

"You worry too much," the two of them said at the exact same time, Dean's voice coming out in a weird mix of octaves that left Sam grinning again. It was Dean in full control – often the result when Cas felt like he'd stepped on toes – who waved the spatula and turned back to the stove. "Alright, already, enough chick-flick moment. You're gonna burn the eggs, Cas. _Again_."

Which sparked a second round of bickering and this time Sam could hear Cas's own amusement in his switches. So Sam didn't bother trying to hide how entertaining it was.

"It's like living with a schizo."

"Hey," Dean was back, pointing the spatula at him after having successfully flipped the last egg. "We take personal offense to that. Schizo's have voices in their heads. What we have is way more like multiple personality disorder."

Sam raised an eyebrow at the both of them.

"What," his brother baulked, turning back to the poke their breakfast unnecessarily, "I read."

"You have a millennia old angel in your head feeding you information," Sam countered.

Dean nodded whole heartedly, peeling the eggs off the pan with care. "I have a walking encyclopedia up here, Sammy."

He turned around, waving the spatula at his head while sliding a plate full of food across the island counter to where his brother was sitting. As Sam caught the plate before it could go too far and slide right off the counter, the older Winchester straightened suddenly, a brilliant gleam in his eye that was entirely Dean.

"Hey, we should go on Jeopardy!"

Sam shook his head, because of course that's where his TV-obsessed brother would jump to, and dug into his breakfast. The eggs weren't half bad, probably because they were only half made by Cas. The angel-hunter combo joined him at the island a moment later with their own plate and Sam sat back, marveling at how this was somehow working.

Oh, he was sure they weren't completely out of the woods yet. Bad days were still a given, and it wasn't like they'd figured out hunting or interaction with anyone outside the bunker. But maybe, just maybe they'd get there.

He went back to his food with a smile on his face as he listened to his brother teach an angel about answering a question with another question because it was the only way to win a game about questions. And also how he was absolutely serious about this, they were talking big bucks here! (Not to mention, the ladies loved the smart ones - to which Sam choked on his coffee and asked if he could get that in writing). It did not take long for Cas to come out and say, for Sam's benefit since the two could absolutely be having this monumentally important conversation silently between themselves, that responding in the form of a question was a needlessly complicated and ultimately pointless requirement for a game. And that, yes, women most certainly did love the smart ones more.

Which led to all-out war, and also the three of them spending the rest of the morning watching re-runs of Jeopardy. Dean might have had a point afterall; Cas knew almost every answer.


End file.
